If even a single person had loved this boy and accepted him unconditionally, the shooting would not have happened.
Look into his eyes and tell me what you see? I see a soul who was not loved. Regardless of his family conditions, if even a single kid or teacher at school had accepted him unconditionally, or if a stranger on the bus had recommended the right book, what might Nikolas Cruz have become?
Go on, keep arguing about gun control, about what measures can be implemented to stop this violence, about what was wrong with this boy...but in a society starved of love, know that these tragic errors will continue. If you want your kids to be safe at school, teach them to look for that kid who is starving for love. Show them what love is and how to give it. You can do the same thing. Learn to love every person you come into contact with, starting with yourself.
This violence is the result of a spiritual crisis. It isn't going to be solved by blaming, shaming, arguing, or punishing (nothing ever is). Love.